Criticism has been levelled at the ambulance service covering Northampton and the NHS's 111 service, after an inquest found woman could have survived if she had not waited nine hours to be taken to hospital.
Diana Gudgeon died of multi-organ failure on May 25 last year, three days after being diagnosed with a water infection by her GP.
But deputy coroner for Northamptonshire, Hassan Shah, has now written to the East Midlands Ambulance Service (EMAS) and NHS 111 in a bid to prevent further deaths.
He says both services failed to warrant Mrs Gudgeon's condition with an emergency response - even though the 78-year-old she had collapsed, had passed out, was confused and vomiting.
As a result - Mrs Gudgeon waited some eight-and-a-half hours before paramedics discovered she was suffering from a deadly urinary tract infection.
"In my opinion action should be taken to prevent future deaths and I believe you AND/OR your organisation, have the power to take such action," Mr Shah writes in the report.
At around 10pm on May 22, 2018, Mrs Gudgeon's condition was reported to the NHS 111 service.
Her medical concerns were then passed over to the East Midlands Ambulance Service (EMAS) Emergency operations Centre.
But even though she was showing signs of central nervous system and neurological problems that required an urgent response - EMAS rated the call as a category three emergency, requiring only a two-hour response time.
At 11.42pm a nurse called Mrs Gudgeon and undertook a further assessment, after which it was found she may be suffering from a urinary tract infection.
Still, no escalation occurred.
At 4.50am a solo-crewed ambulance car arrived at the home - though the paramedic only gave Mrs Gudgeon oxygen before leaving.
Finally, at 6.30am an ambulance arrived at the home, some eight-and-a-half hours after the initial call.
It was determined she may be suffering from infection and sepsis and she was taken to Northampton General Hospital at 7.10am.
She died two days later.
Mr Shah's report raises several concerns about the way her emergency was handled after a consultant at the inquest said she may have survived if she was given antibiotics much earlier.
In particular, he questioned the effectiveness of both services' phone triaging system - neither of which managed to recognise the extreme danger Mrs Gudgeon was in.
Also, EMAS was 10 ambulances short on the shift that night, but no additional vehicles were made available.
It was also noted during the inquest that EMAS would have likely prioritised the call higher had it been made to 999 and not the 111 non-emergency number.
"It was suggested in evidence that if the same facts are inputted into the ‘999’ AMPDS triaging system they are likely to allocate a higher priority to the call than the ‘111’ Pathway triaging system would," Mr Shah said.
The coroner asked EMAS to respond as to how it would prevent the such a fatality occurring again.
Director of quality improvement and patient safety at the ambulance service, Nichola Bramhall, said: “I offer my sincere condolences to Mrs Gudgeon’s family for their sad loss.
“Patient safety is a priority and is viewed extremely seriously in our organisation.
“In addition to a full response to the issues raised, we have included in our formal reply an invitation for the Coroner or a representative to visit our Emergency Operations Centre to allow us to demonstrate the systems and processes in place. We will also evidence the improvements made to patient services following significant additional investment announced by our commissioners in 2018 (£9million), and the subsequent recruitment campaign - the largest in EMAS’ history with over 200 additional staff recruited - and purchase of new and additional ambulance vehicles. This is in addition to efficiencies made at EMAS in recent years to help address a fundamental gap between the resources (staff and vehicles) needed and the funding received.
“Our plan is to recruit a similar number of frontline staff during 2019/2020 which will help us to continue to improve patient services, and to meet the national ambulance service performance standards. We know this comes too late for Mrs Gudgeon and her family, and deeply regret this.
“Following a CQC inspection in April and May 2019 EMAS has improved its rating from ‘requires improvement’ to ‘good’ overall and ‘outstanding’ for caring. Our quality improvement plans are designed to compliment the further investment this year to help us continue to improve and develop our patient and staff services. For more information see our media release about the latest CQC rating https://www.emas.nhs.uk/news/latest-news/2019-news/emas-rated-good-overall-and-outstanding-for-caring-in-latest-inspection/."